1. Field of the Invention
The invention relates to a method using a pointing device for transferring information e.g. at a microcomputer having a display, or at the user interface of a mobile phone, and to a device combination realizing the method.
2. Description of the Prior Art
In the development of small size portable data processing and communications equipment we are repeatedly faced with the problem how to realize flexible, versatile and user friendly data entering. For instance present day notebook microcomputers and mobile phones have comparatively small displays, and the keyboard sizes are very limited. Thus it will be a slow and cumbersome process to enter data in these devices, so that in practice only simple and short messages can be transferred through the user interface.
Different solutions to the above problem have been found and also put into use. Such solutions are presented e.g. by the user interfaces based on a touch screen. Different types of touch screens were discussed in the Finnish computer paper PROSESSORI, n:o 1/94, p. 31 to 33 "Kosketusnaytolla helpommin" (`Easier with a touch screen`). The article mentions analog methods based on capacitive, resistive, and force measurement techniques. Of the matrix methods the article mentions infrared, acoustic and possibly also resistive contact detection. This article, however, discusses touch screen applications primarily for larger monitors based on the cathode ray tube technology. FIG. 1 is a figure presented in said article, which shows how in principle a certain point P on the display can be selected with the finger H, and how changes in the capacitance are detected in the horizontal and vertical directions by the display's detection circuits S, which then produce a signal to be processed by the electronics of the display device.
For portable applications we know e.g. so called pen computers or PDA devices (Personal Digital Assistant) are on the market in the form of devices such as Apple Newton MessagePad, Sharp ExpertPad, or Casio XL-7000. These are microcomputers which easily fit in the hand and have no conventional keyboards, but data is entered by writing normal handwriting with a special pen on the touch screen of the device. Alternatively a keyboard picture corresponding to a standard keyboard may be activated on the device display, whereby the key positions are pressed with the tip of the pen. Then the display is realized by liquid crystal or LCD techniques, whereby the input section comprises a transparent digitizing layer over the display layer. The digitizing layer comprises for instance a plurality of digitizing points which are located in a matrix, and which as a result of a contact generate a physical response corresponding to the point of contact. The response is transformed into an electrical signal and in logic circuits it is interpreted into digital information. With the LCD technology the identification of contact points can be realized by different known methods, which for instance are based on the absorption of acoustic surface waves in the contact point, on infrared transmission and reception, on a change in the capacitance and a resulting change in frequency, on a change in pressure caused by the contact which is detected by a strain gauge or a piezoelectric transducer, on mechanical switch designs, and so on. One possibility is also to use the change of the magnetic field or the electromagnetic resonance to detect the point of contact.
FIGS. 2 and 3 illustrate a pen computer application presented in our patent application FI-941629 (the application's FIGS. 1 and 3b, respectively). FIG. 3 shows a mobile phone 31 and a display comprising layers 32, 33 on top of one another. The display also extends under the virtual keys 35. A permanent keyboard is located at 36. In this invention the pointing with the pen at a desired key location is aided by a sheet 34 provided with holes. In FIG. 2 it is shown in section, and its surface 11 has recesses 12, into which a pen is easily directed. A push with the pen 14 activates the transducer 13. In this case the transducers could be realized by keys in different technologies, such as mechanical miniature keys, membrane keys, or digitizing points on a digitizing pad or touch screen.
For instance an electromagnetic resonance method could be used when the above transducer is realized, see-figures 4 and 5. Then the pointing device, the pen 51, receives its operating power through the electromagnetic radiation created by the varying inductive field of the sensor table 41 and stores the energy in its own coupling circuit 52. The surface of the sensor table 41 is e.g. the glass sheet of an LCD display, and the electromagnetic radiation is created by resonant circuits under the display sheet 41, which are supplied by any suitable signal processing circuit 45. The resonant circuit 42 comprises a main capacitor and a coil. The pen 51 includes a resonant circuit 52 comprising a coil and a capacitor, whereby this circuit receives, stores and discharges a signal at the same frequency which it received from the sensor plate. When the display surface 41 is touched with the pen 51, the capacitance of the pen's electrical circuit will change, causing a mutual chance both in the received and in the transmitted signal. This causes a phase shift in the resonance frequency. The position of the pen 51 on the screen 41 is determined with the aid of the signal strength.
The above presented pen 51 can also include a lateral switch, which can be used to start a predetermined function in the receiving device 41. The state of the lateral switch can be detected e.g. by a change in the phase shift and/or in the frequency.
In order to automate data acquisition we know various equipment, of which we could mention scanners, for instance hand-held scanners, and bar code readers. A typical scanner assembly comprises the actual reader device, or a device which reads pictures and/or text and encodes them into an electrical signal, and further a cable and an interface card, through which the signal containing the scanned information is transformed into a form which can be processed e.g. by a computer. Alternatively the cable could be connected to a microcomputer's serial or parallel port through which the scanned information is read into the computer. In many cases the signal generated by the scanner is processed as such, in a bit map form. On the other hand the signal can be processed by a suitable program which detects the pixel position information generated by the scanner and combines these pixels in a suitable way to generate either simple lines or preferably e.g. characters. Character recognition programs have been developed into quite versatile programs, and now there are programs on the market which automatically can recognize different fonts and which can be "taught" to recognize different handwritings.
Bar code readers are quite widely used, for instance at shop check-outs where product information and prices are read and entered from the scanner through a cable/wire interface to the check-out computer. In the industrial production and storage field there are also different identification tasks where bar code readers are used. One typical application of a hand-held bar code reader is stocktaking, whereby a person performing the stocktaking with the aid of a reader identifies the contents of bar code stick-on labels fastened on the products and/or product packages. The collected information is stored in the memory of the bar code reader, and when the stocktaking is ended the data stored in the reader is discharged through a suitable cable interface to a microcomputer with a storage bookkeeping program, into which the collected data is entered. In addition to the mechanical connections the user must usually perform operations related to a microcomputer program, for instance enter instructions through a separate keyboard so that the collected data can be stored in the correct memory position determined by the program.